The prior technology with respect to the ordinary two-layer mutual capacitance touch screen can realize real multi-touch, nevertheless, two-layer electrode plates are required to be laid, most of which are made of transparent conducting material Indium Tin Oxide (hereinafter referred to as ITO), thus, giving rise to high manufacturing cost. In addition, structure for most of the touch screen with respect to the prior technology includes Glass/Glass structure (hereinafter referred to as GG structure), Glass/Film/Film structure (hereinafter referred to as GFF structure), and One Glass Solution structure (hereinafter referred to as OGS structure). The adoption of such technological structures requires two layers of ITO, or ITO used to drive electrode and middle bridge for ITO used as sensor electrode. Production processes for such practices are all complicated, so the cost is high.
Besides, there is also the scheme for single layer mutual capacitance touch screen with respect to the prior technology, single layer ITO can be used as the electrode for mutual capacitance. As is shown in FIG. 7, a kind of electrode plate is placed in the clearance between the other kind of electrode plates, electrodes of the same line are connected to the outside of the screen through transparent ITO lead, then, electrodes of the same line are connected to the exterior of the effective touch zone. Both technology and cost for single layer mutual capacitance touch screen are more downsized than that for traditional two layer mutual capacitance, nevertheless, its electrode pattern is relatively complicated. There are numerous lines (usually more than 150 lines are required) connected to the outside of the active zone for touch screen, thus, high requirement is imposed on the precision of production process, at the meantime, yield rate will also be reduced.
The simplest electrode pattern is a single layer self-capacitance touch screen scheme, consisting of complementary near-triangle electrodes, as is shown in FIG. 8. Electrode pattern for such scheme is simple, with comparatively fewer lines, namely, about 30 lines are required for the touch screen whose dimension is around 4 inches. However, under some circumstances, self-capacitance touch screen adopting such near-triangle complementary pattern fails to realize multi-touch, because with respect to the method of computing coordinate data for touch points, it calculates coordinate adopting touch change rate at horizontal direction and touch change in center of gravity at the vertical direction. For example, when multi-touch points occur on the same horizontal line, coordinates at vertical direction for all touch points detected worked out adopting touch change in center of gravity are the same, coordinates at horizontal direction can't be calculated for various points detected can't be distinguished via touch change at horizontal direction, consequently, multi-touch can't be realized on the same horizontal electrode. For the same reason, multi-touch can't be realized on the same vertical line. Therefore, defect is obvious with respect to the multi-touch function for the above single layer self-capacitance scheme.